Mobile communication devices are popular for business and personal use. Such devices include Personal Digital Assistants (PDAs), cellular phones and smart phones. These devices provide wireless two-way voice and data communication over wireless networks such as GSM/GPRS, CDPD, TDMA, iDEN Mobitex, DataTAC, EDGE or UMTS networks, and broadband networks like Bluetooth® wireless technology developed by Bluetooth SIG, Inc., Bellevue, Wash., U.S.A. and variants of IEEE standard 802.11.
Any electric current generates a magnetic field as given by the Biot-Savart law. If there is second electric current of similar magnitude and of opposite direction in close proximity to the first electric current, a similar but opposite magnetic field is generated. This second electric current is said to match the first electric current and effectively cancels the magnetic field generated by the first electric current. This technique of “matching currents” is a useful method to suppress magnetic fields.
It is desirable that the electromagnetic fields generated by mobile communication devices be minimized for health reasons and to reduce interference with other nearby electronic devices.